The present invention relates generally to catheters for performing medical procedures. More particularly, the present invention relates to guide catheters for use in angioplasty procedures.
Intravascular diseases are commonly treated by relatively non-invasive techniques such as percutaneous transluminal angioplasty (PTA) and percutaneous transluminal coronary angioplasty (PTCA). These angioplasty techniques typically involve the use of a balloon catheter. In these procedures, a balloon catheter is advanced through the vasculature of a patient such that the balloon is positioned proximate a restriction in a diseased vessel. The balloon is then inflated and the restriction in the vessel is opened.
The most widely used form of angioplasty makes use of a guide catheter positioned within the vascular system of a patient. The guide catheter assists in transporting the balloon dilation catheter to the restriction in the diseased vessel. During this procedure, the distal end of the guide catheter is typically inserted into the femoral artery located near the groin of the patient. The guide catheter is urged through the vasculature of the patient until its distal end is proximate the restriction. In many cases, the distal end of the guide catheter is positioned in the ostium of the coronary artery. The balloon catheter may then be fed through a lumen in the guide catheter.
It is desirable that a guide catheter incorporate a level of rigidity which will allow it to be passed through the vascular system without folding or buckling. To assist in directing the distal tip of the guide catheter to the coronary ostium of the patient, the distal portion of the guide catheter may include one or more bends. The distal tip of the guide catheter is typically formed from relatively soft, flexible material to avoid trauma to arterial vessels, and allow flexing of the distal tip to aid the guide catheter in traversing desired arterial branches.
In some applications, it is desirable to form a guide catheter by bonding together two or more tubular sections in order to achieve a more rigid proximal portion and more flexible distal portion. It may also be desirable to have the distal portion of the guide catheter shaft be comprised of one or more tubular sections which are adapted to be formed into a curved shape. As described above, these curves aid in directing the distal tip of the guide catheter to the coronary ostium of a patient. In some embodiments, it is desirable to have a distal portion of the elongate shaft which can be heated and bent to a desired shape, then allowed to cool. By way of a second example, it may be desirable to include one or more tubular sections having a reinforcement braid, and one or more additional tubular sections having no braid. A braid or other reinforcement member is used to strengthen the tubular section and increase torque transmission. When a guide catheter is comprised of more than one generally tubular section, these sections are joined together at joints where the distal end of a first tubular section is affixed to the proximal end of a second tubular section.
The present invention relates generally to catheters for performing medical procedures. More particularly, the present invention relates to guide catheters for use in an angioplasty procedure. A guide catheter in accordance with the present invention includes an elongate shaft. A hub may be affixed to the proximal end of the elongate shaft and an atraumatic tip may be affixed to the distal end of the elongate shaft. The elongate shaft is preferably comprised of more than one generally tubular section.
A method of bonding tubular members in accordance with the present invention may begin with the step of forming a joining region on the distal portion of a first tubular member. The joining region preferably includes a plurality of ribs and a plurality of areas with a generally reduced diameter relative to the ribs. A variety of manufacturing methods may be used to form the ribs including material forming processes and material removal processes.
A method in accordance with the present invention includes the step of positioning a mandrel. so that at least a portion of its length is disposed inside the lumen of the first tubular member. The joining region of the first tubular member is then inserted into the lumen of a second tubular member. After the joining region of the first tubular member is inserted into the lumen of the second tubular member, the mandrel will be positioned so that at least a portion of the length thereof is disposed inside both the lumen of the first tubular member and the lumen of the second tubular member.
The assembled tubular members are then subjected to heat and pressure proximate the joining region of the first tubular member. A number of methods may be used to heat the tubular members, including convection, conduction and radiation. The second tubular member is thus bonded to the first tubular member at the joining region.
Having formed a bond, the assembly is then allowed to cool. The assembly may be submersed in a relatively cool fluid to speed cooling of the assembly. Examples of fluids which may be suitable for some applications include water and air. Relatively cool air may also be impinged onto the assembly. After the catheter assembly has cooled, the mandrel may be removed from the lumen of the catheter assembly.
An additional method in accordance with the present invention includes the step of positioning a shrink wrap sleeve over both tubular members in an area proximate the joining region of the first tubular member. After the sleeve is disposed about the tubular members, heat is applied to joining regions to form a bond. At an elevated temperature, the shrink wrap sleeve applies the pressure necessary to form the second tubular member around the joining region of the first tubular member. Having formed a bond, the assembly is then allowed to cool. After the assembly has cooled, the sleeve and the mandrel are removed.
An additional method in accordance with the present invention may be used to bond a hub to a tubular member. This method typically begins with the step of forming a bonding region on the tubular member proximate the proximal end thereof. The bonding region typically includes at least one rib and at least one area of generally reduced diameter relative to the rib diameter. The proximal portion of the tubular member is then positioned inside the cavity of a molding tool. Molten plastic is then injected into the cavity of the molding tool and allowed to cool.